THE H^JUOELAGELLATES. 255 



parts of the East are liable, and wliicli are known by sncli 

 names as Delhi boil, ''bouton d'Alep/' oriental sore, tropical 

 ulcer, etc. The latter type of disease is one of localised 

 infection, tlie organisms being restricted to the neighbour- 

 hood of the sore or ulcer, whereas in the former there is a 

 general infection, the parasites spreading to all parts of the 

 body, and being met with in the liver, spleen, bone-marrow, 

 etc., and (rarely) in the peripheral circulation. No actual 

 connection has yet been established between the parasites of 

 local and general infectivity.^ 



Medical opinion on the whole is at present inclined to 

 regard both these types of disease as being due to different 

 manifestations of the same kind of parasite, the differences 

 in symptomatology being largely explainable by the different 

 habitat of the parasites in the two cases." lu view, however, 

 of this different habitat and behaviour it is very uncertain 

 whether the organisms, notwithstanding their apparent simi- 

 larity, really belong to one and the same species. Bearing in 

 mind the very slight morphological differences to be found with 

 any constancy among many Mammalian Trypauosomes, which 

 are, on other grounds (habitat, behaviour towards immu- 

 nising sera, etc.), regarded as belonging to distinct species, 

 it is not unlikely that the same holds good here also. But 

 the question is still far from being settled.^ 



' In other words, the parasites, when limited to the neighbourhood of an 

 ulcer or sore, never seem to become generally distributed throughout the 

 body, and produce the febrile type of disease ; although persons suffering 

 from the latter may have skin eruptions or papulae, leading to the formation 

 of small ulcers which somewhat resemble "oriental sores." 



' James (126j is a little inclined to doubt whether the organisms are 

 really the cause of such a severe illness as Kala-azar, although recognising 

 the constancy of their occurrence. He hesitates because of the great 

 resemblance which they bear to the parasites of the other type of disease 

 (oriental sore, for examplej, and the very different effects to be accounted 

 for (see next footnote, however). 



■' ]\lanson (132) puts forward the interesting hypothesis that the two 

 types of disease, of such different gravity, may bear to one another the same 

 relation that variola and vaccinia do. He suggests that the germ of Delhi 

 boil may be that of Kala-azar, which has become attenuated by passing 



